Thermostat control



July 11, 1933.

e. FRANTZ ET AL 1,917,880

THERMOSTAT CONTROL led March 11, 1932 INVENTORS 5.6.FRANTZ 8.5. M? CUTCHEN Y W. van B.ROBERT5 ATTORNEY Patentecl July 11, 1933' SAMUEL G. reanrz, BRUNSON s. McceTc nm-ann; wnmnn VAN B. ROBERT$OF PRINCETON, NEW JERSEY; sari) rnnnrz (AND SAID non McCUTGHE-N rissrenons o, sar

TH'ERMosTsr contract Application filed arch 11, 1932;Sria'l 1%.: 595,168..

his invention relates to temperature control devices and particularly to ineans'responsive to temperature changes adapted to maintain the temperature in any desired room substantially within predetermined limits.

One of the objects of this invention is to provide nieansthrough which a relatively large controlling forceis obtained in response to a relatively small'change of: temperature.

Another object of the invention is to provide a novel means for cascading two or more heat-operated devices so as to produce an amplifying effect. I

Anotherobject of theinvention is to provide an arrangement of two or more heat-operated devices otdifierent sensitivity and having the one of greater sensitivity control the one of lesser sensitivity. l

Other objects of the invention will appear fromtlie following description taken together with the 'drawing'which forms a part of this specification, and in which v Figure 1 shows a general View, partly broken away, of the invention as applied to control the temperature of 'aroom heated by a radiator; and,

Figure 2 is an'enlarge'd sectional certain elements shown in Fig.1.

The present invention is particularly use ful in cases wherein it is desirable to maintain a substantiallyconstant flow of heating vapor from a source to a radiator and wherein the control of'heat transfer from. the radiatorfto the room is to be accomplished by means of a thermostat operated shutter arrangement which controls the intensity of flow of convection currents around and through. the radiating surfaces of the radiator. In such cases elaborate systems in-,

trical circuits j have heretofore. been found necessary due to the fact that thermostats capable of producing of themselves a great enough force to operate the shutters for small changes in temperature cannot be produced. This results from the fact that thermo-eleinents whether they be bi-metallic, fluid expansion or'of any other type, are essentially heat engines, and cannot possibly work with a greater 'efiiciency than an ideal heat cascading effect .lHG-Qllllfillt is enabled work on a temperaview of able shutters These'shutters are arranged engine In C {in 177 MOIluDgOil a ijarnot cycle This means Uiiat 01 a given amount working substance the power output per cycle changes rapidly with temperature difrerence upon which it operates,

In the presentnivention, theabove' factor is overcome by the incorporationof a novel whereby a high-power therture difference of inanyt-iines the permitted roomtemperaturevariation. It isthus enabled-{to deliver per cycle manyti'mes as much power V as would be delivered bythe same-element operating directly on room teingerature..- r tating it another way, for, 1 the same" power outputthe size and cost of the "necessary thermo=eleinents are greatly i'educed.f""- V 'Referiing to the form of the invention shown in the drawingf2- representsa radiaim-(h ving the customary teed pipe '4. through-which the iiotvapor is'ied into the radia t o'r. Radiator 2 isprovided with an enclosure ihWlllCll maybe constructed of 7V any suitableinaterialt Th radiator enclosure 1 comprises a top portion 3 having a small screened'openiiig 12 and a side por tion having movably mounted thereon movso' that they, all may be operated siinultan ously and for-accomplishing the operation thereof there s provided, a connecting rod '10 which is actuated by a9 pivotedleverv Gattached to the movable end of a' comparativelylarge thermostat 7. An insulating shield ing sleeve arrangement 9'1S disposedadjacent the thermostat so as to insulate it from the hot sections ofthe radiator. A movable deflector ll iivoted at 12 to the thermostat housing is a apted to form a downward con tinu'ation of the insulation sleeve 9. An inverted iunnel shaped fiue13 is suitably dis- 1 posed so asto receive and guide hot air from the hot surfaces ofthe radiator 2. A second posed relative to the pivoted deflector 11 that fine 15 preferably made oi'suitable partial I when the. deflector is rotated clockwise about pivot 12 (Fig. 1) the hot air rising in flue 13 is deflected throughll and made to pass through sleeve 9 and thereby forced to pass around thermostat7, whereas when deflector 11 is rotated counterclockwise the room temperature air rising in flue 15 is deflected through 11 and forced to pass around thermostat 7.

In this way thermostat 7 may be subjected to large temperature differences since the room air passing up flue 15 is considerably cooler than air off the hot radiator surfaces passing up flue 13. A sensitive pilot thermostat 1 1 which may be considerably smaller than thermostat 7 is supported in any suitable manner within the lowerportion of flue 15. Thermostat 1 1 is, therefore, responsive to the temperature of the air drawn from the room by the normal convection current of the radiator. As, illustrated, thermostat 14 is arranged so that its lower end is the movable portion which end is attached through a lever 16 to one end of rod 17. The other end of rod 17 is attached to an arm 18 which is fixed .to the movable defiector ll.

It is seen that in the arrangementdescribed movements of lever 16 due to small changes in room temperature swing deflector 11 so as to apply large temperature changes to thermostat 7 V 1 7 I The operation of the system disclosed is as follows:

In the positions of the parts shown in Fig. 1, the room is at or above the temperature desired, therefore, the thermo-element 1 1 is expanded and the shutters 5 are in the act of being closed in Fig. 1 thereby reducing the transfer of heat to the room to a minimum. If now the room temperature drops a few degrees below the desired temperature, thermostat 14 collapses thereby pushing up .rod 17- and swinging deflector 11 counter-. clockwise to the position shown in Fig. 2.. This allows a current of cool air to pass over thermo-element 7 which collapses causing lever 6 to operate and open shutters 5 which are shown prior to being opened in Fig. 2

thus increasing the intensity of heat transfer to the room. Then when the temperature of the roomis again up to the desired point, 1 1 expands pulling down rod 17 and-rotating deflector 11 to the position shown in Fig. 1 soas to guidehot air from flue 13 and pass it over 7 thereby quickly raising the temperature of 7 by a large amount, sayr20 .or degrees. This makes available a large amount of power which working through lever 6 and connecting rod 10 closes shutters 5. In this way, avery small temperature change in the room is able to control a relatively large amount of power for operating the shutters without the use of an inconvenient large amount of working substance in any thermo-element. V 1

From the operation of the system it will be seen that the flue 15 should be partially heat conducting in order to heat the air therein to a slight degree and thereby cause air from the room to rise in the flue. It will also be seen that the screened opening 12 at the top of the enclosure 1 while not absolutely necessary is of some use to permit a direct passage for the controlling air especially when the shutters 5 happen to be closed. It

is to be understood that the opening 12 is comparatively small and that therefore its effect upon the temperature of the room is negligible.

It will be understood that various forms of the invention other than that described above may be used without departing from element also mounted within said housing I and responsive to the air temperature entering the housing and a deflector device controlled by said pilot thermo-element for con trolling the temperature around said main thermo-element,

2. The combination with a radiator having a housingin which there is disposed at least one thermostat controlled movable shutter, a flue for receiving hot air from the hot surfaces of the radiator, a second flue for receiving air at. room temperature, a deflector device adapted to deflect air from either of said two fines to said thermostat and means controlled by temperature changes of the room air for controlling the operation of said deflector device; 7

3 In a system for controlling the temperature of a circulating medium, a heat source,

an enclosure for the source and adapted to allow aflow of the medium therethrough and around the source whereby heat is trans- I ferred from thesource to the medium and the medium heated thereby, said enclosure including a movable shutter for determining the rate of flow of the medium therethrough, a thermostat for operating theshutter, said thermostat being shielded from the source, a flue for receiving and confining the flow of a portion of the medium entering the enclosure, a movable deflector device adapted in one position to receive heated medium flowing through said enclosure and direct it toward the thermostat whereby the thermostat is exposed to the temperature of the heated medium and in another position to receive the medium flowing in said flue and direct it toiPYOVltlQQ atleast two paths of co-nlined fiowtrir "the 'air therei-lu-ough one of thrrpaths leading a"port1on of the air entering the enclosure .urc' for determining the operation. of

4. l a system for'controlling thc tempera a roomwherein theroom air is allowed topa overheat transfer-means, an enclosure tor-said means adapted to allow the air to' 5 llow -tncrethrough and over theheat transfer means, said enclosure beingarrangedsoas to over the heat transfer means whereby'heat is given up h no and absorbed by the other, theotherotsaid paths leadinganother portion of the aircnte ring-the enclosure therethrough but substantially insulating it from the heat transfer means, whereby the last.

named portion of the air is prevented from being ailccte'd by coming 1n contact-with the heat transfer means to any substantial dcgree, controllable means for dcterminingthe rate of How of the air through the first path, a prim ary thermostat haying connection with the controllable means to operate the same, a secondary thermostat responsive to temperature changes of the air entering the second named path and means controlled by the secondary thermostat for exposing the primary thermostat to the air tlowing in either of said paths in accordance with the variations in temperature of the medium entering the second named path.

5. In a system for controlling the temperature of a circulating medium, a heat source, an enclosure for the source and adapted to allow a low of the medium theretl'n'ough and over the source whereby heat is trans erred from the source to themedium, said enclosure including a thermostat controlled movable shutter adapted to control the rate oi How of the medium through the enclosure, a line within the enclosure adapted to receive and direct heated medimn from the heating surfaces of the source, a second flue for receiving and directing a portion or the medium enter ing the enclosure. a deflector afdapted'to rcceive and subject the thermostat to the medium from either of the two fines and means controlled by temperature changes of the medium entering the second named flue for determining the operation of the deflector.

S. The system described in claim 5 wherein the last named means comprises a second thermostat mounted within the second named flue.

7. In a system for controlling the temperature of a circulating medium, a heat source, an enclosure for the source and adapted to allow a flowv ot' the medium therethrough and. over the source whereby heat is transferred from the source to the medium, said enclosi'ne including -'a fil-iermostat controlled mow. able shutter iilevi'ce adapted to control the i -ate 'o'f llow of the 'medium through the enclosure, a "line within the enclosure adapted -to receive and direct heatedniedimn "from the i'eating surfaces of -t'l'ie'source,'a s :tlue "for receiving and -'(liI-'ecting aqiiortion-ot' -=th m e'dirun en tering the encl osure ,a d etlector adapted 'rto deceive thes-inedimn among thr0 u'gh eit her ot the two fluesand 'ezl pose the --t hermostat thereto, means controlled bytenipera ture changes of .th'e ane'dium entering the second: named lluex'ror deter-mining theoperaion of thedeflcctoigand au openingprovided I in 'therenclosure ai-rdrar'r-angetl with' resp'ectxto the second named fiueso as to allow-thermopaths of confined flow for the medium'the'rethrough one of said paths leading a portion otthe medium entermg the enclosure over the source whereby heat is transferred from the source to the medium, the other of said paths leading another portion of the medium entering the enclosure therethrough but substantially insulating it from the source whereby the last named portion of the medium. is heated only to a tractionof the temperature to which the first named portion of the medium is heated, controllable means for determining the rate of flow of the medium through the first path, a primary;

thermostat having connection with the controllable means to operate the same, a secondary thermostat responsive to tempera-- ture changes of themedium entering the second named path, and means controlled by the secondary thermostat for exposing the primary thermostat to the medium flowing in either of said paths in accordancewith the variations in temperature of the medium entering the second named path.

10. The system described in claim 9 wherein the primary thermostat is normal- 1y sensitive only to' wide temperature changes and the secondary thermostat; asv

compared with the primary thermostat. is

normally sensitive to temperature changes which are relatively small. I

11. In a system for controlling the tem-- perature of a circulating medium, a heat" source, an enclosure for the source and adapted to allow a confined flow of the mevcond.

'fcliunntoflow at least through said second anamcd flue 'ir'respectlve 0f "the "conditi on of closure being arranged so as to provide two" posed to-a circulating current of the medium heated by passage thereof over the source and means operated by the primary thermostat for exposing the secondary thermostat to a different circulating current of the medium. I

12. In a system for controlling the temperature of a medium, a-heat source, an enclosure surrounding the heat source and adapted to allow a confined flow of the me dium therethrough and over the source whereby heat is transferred from the source to the medium, controllable means'for determining the rate of flow 0t the medium I through the enclosure, a primary thermostat mounted Within the enclosure and responsive to changes in temperature of the medium entering the enclosure, a secondary thermostat having connections with the controllable means to operate the same and normally exposed to a current of the medium heated by passing over said source, and

,means operated by the primary thermostat for controlling the temperature of the medium flowing around the secondary thermolao stat.

SAMUEL G. FRANTZ. BRUNSON S. MoGUTCI-IEN.

l VALTER VAN B ROBERTS. 

